1. Field of the Invention
The present invention relates a rotary switch and more particularly to the use of a spring member in a rotary switch, which is durable in use and greatly prolongs the service life of the rotary switch.
2. Description of the Related Art
A switch is a requisite device for controlling the supply of power supply. By means of a power switch, the user can cut off power supply when its supply is not necessary, preventing a disaster. A power supply control switch can be a normal-close switch that is switched to an open-circuit status to switch off power supply when the supply of power supply is not necessary. Alternatively, a power supply control switch can be a normal-open switch that is switched to a close-circuit status to switch off power supply when the supply of power supply is not necessary. Therefore, any product that consumes power supply uses a power switch. A power switch obtains power supply by means of electrically connecting two electrodes to close the power circuit. When the two electrodes are disconnected, the power circuit is off. In some conditions, a switch can be used for the control of an electrical signal, for example, for cutting off power supply to produce a triggering signal that drives a control circuit to start an electric device.
FIG. 1 is an exploded view of a conventional rotary switch. According to this design, the rotary switch is comprised of a holder base 10, a springy frame 20, a rotary handle 30, and a top cover 40. The holder base 10 holds two metal contact plates 12 in a parallel manner on the inside space at one side. The metal contact plates 12 each have a vertical mounting legs 121 downwardly suspending at one end and inserted through a respective through hole 11 to the outside of the holder base 10, and an electric connection portion 122 horizontally disposed at the other end, and a contact 123 raised from the top side of the electric connection portion 122. The metal connection plate 13 comprises a mounting leg 131 perpendicularly downwardly extending from its one end and inserted through a respective through hole (not shown) of the holder base 1 for mounting, two electric connection portions 132 horizontally disposed in parallel at its other end, and two contacts 133 respectively protruded from the bottom sides of the electric connection portions 132 for contacting the contacts 123 of the two metal contact plates 12 respectively.
The springy frame 20 is provided at the top side of the holder base 10. The rotary handle 30 is pivoted to a pivot shaft 14 of the holder base 10. The top end of the rotary handle 30 is inserted through an axle hole 41 of the top cover 40 that is covered on the holder base 10 to hold down the springy frame 20. The rotary handle 30 has a bottom actuating block 31 suspending inside the springy frame 20. The bottom actuating block 31 comprises two opposite flat peripheral walls, two arched peripheral walls between the flat peripheral walls, a bottom protrusion 32 and a bottom recess 33.
When the rotary switch is not operated as shown in FIGS. 2a and 2b, the two opposite flat peripheral walls and two arched peripheral walls of the bottom actuating block are kept spaced from the inside wall of the spring frame 20, at this time the bottom recess 33 receives a slotted triangular holding down portion 124 of the electric connection portion 122 of one metal contact plate 12, allowing the material spring power of the respective metal contact plate 12 to force the respective contact 123 into contact with the associating contact 133 of the metal connection plate 13, and therefore the rotary switch is in a normal-close status.
On the contrary, when the user rotates the rotary handle 30 on the pivot shaft 14 through an angle, as shown in FIGS. 3a and 3b, the arched peripheral walls of the bottom actuating block 31 forces the springy frame 20 to deform, and at the same time the bottom protrusion 32 of the actuating block 31 is pressed on the slotted triangular holding down portion 124 of the electric connection portion 122 of one metal contact plate 12 to force the respective contact 123 downwardly away from the associating contact 133 of the metal connection plate 13, producing an electrical signal to an electric home appliance, for example, the control circuit of a washing machine. Upon receipt of the electrical signal from the rotary switch, the control circuit is caused to start the motor of the washing machine. After production of the electrical signal, the springy frame 20 releases energy to return the rotary handle 30 to its former position.
According to the aforesaid design, the springy frame 20 is molded from plastics. It starts to wear after a long use, and will easily cause elastic fatigue due to the effect of weather and temperature. Therefore, an improvement in this regard is necessary.